Known as mitochondrial donation, the in vitro fertilization technique involves replacing faulty mitochondria inherited from the mother with the healthy mitochondria of another woman as a way of preventing mitochondrial disease from being passed on to a child.

Sally Cheshire, the fertility regulator's chair, announced the approval Thursday during its annual conference.

"I can confirm today that the HFEA has approved the first application by Newcastle Fertility at Life for the use of mitochondrial donation to treat patients," Cheshire said afterward.

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"Patients will now be able to apply individually to the HFEA to undergo mitochondrial donation treatment at Newcastle, which will be life-changing for them, as they seek to avoid passing on serious genetic diseases to future generations."

The facility will now need to apply to conduct the process on a case-by-case basis.

What are mitochondria?

Mitochondria are small structures found in our cells that generate the cellular energy used to power every part of our bodies.

Mitochondria have their own DNA, which controls only mitochondrial function and energy production.

This is separate from our "nuclear DNA," which makes us who we are and determines appearance and personality.

Source: Wellcome Trust Centre for Mitochondrial Research

Mary Herbert, professor of reproductive biology at the Newcastle Fertility Centre and Newcastle University, said the team was delighted by the decision to grant the clinic a license.

"Many years of research have led to the development of pronuclear transfer as a treatment to reduce the risk of mothers transmitting disease to their children," Herbert said.

"It's a great testament to the regulatory system here in the UK that research innovation can be applied in treatment to help families affected by these devastating diseases."

Professor Allan Pacey, a fertility expert at the University of Sheffield, also welcomed the announcement as "very good news and a great day for science."

This mitochondrial DNA is inherited only from the mother through her eggs.

If the mother's mitochondrial DNA is faulty, it is possible that she may pass on a number of rare but serious mitochondrial diseases, including muscle weakness, diabetes, heart problems, epilepsy and stroke-like episodes. In serious cases, they can lead to death.

"From the first proof of concept studies to today, there has been an excellent, independent regulatory process which consulted patients and the public at every stage," said Dr. Jeremy Farrar, director of the Wellcome Trust.

"Now we must give the first patients and their doctors the time and space to discuss the next steps with the patience, sensitivity and scientific rigor that they have displayed throughout."

The UK will probably not be the first country to have children born through the three-person technique.

A Jordanian couple and doctors in New York claimed they performed the procedure in Mexico, with a child being born last April.